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    <h3>Overview</h3>
    <p>RoverGauge is a software utility intended for diagnostics and testing of the Lucas 14CUX engine management system, which was fitted to Land Rover vehicles produced from 1990 to 1995, as well as some sports cars produced by TVR, Morgan, Ginetta, and Marcos.</p>
    <p>For RoverGauge to work, the computer must have a specially modified USB-to-serial converter. Instructions for building this cable can be found on the <a href="http://code.google.com/p/libcomm14cux/wiki/HardwareInterface">libcomm14cux wiki page</a>.</p>
    <h3>Main display</h3>
    <ul>
    <li><b>Tune:</b> The tune revision of the firmware in the ECU, such as "R3360". Note: this number was not always updated by third-party firmware sources for low-volume automakers such as TVR. In that case, multiple different tunes may share the same tune number.</li>
    <li><b>Ident:</b> An additional identifier that is updated independently of the Tune number.</li>
    <li><b>Checksum fixer:</b> A byte of data used to fix the checksum of the ROM image. This can be used to further identify a ROM image beyond the Tune and Ident values.</li>
    <li><b>MIL:</b> Lit red when the malfunction indicator lamp (MIL) is being lit by the ECU. When the engine is running, this typically means that one or more fault codes are set. The MIL is also lit under other circumstances (such as when the ECU is powered on but the engine has not been started.) Note that there are some fault codes that do not cause the MIL to light.</li>
    <li><b>Communications:</b> The green lamp is lit when the software is successfully reading data from the ECU, and the red lamp is lit when there was a problem communicating with the ECU (caused by a bad connection, disconnected cable, misconfigured USB adapter, or other problem.) Both lamps will be off if there has not been any attempt to read from the ECU.</li>
    <li><b>Engine temperature:</b> Displays the temperature read by the engine/coolant temperature sensor. The green and red colored areas (representing "nominal" and "warning" temperature levels) are approximate.</li>
    <li><b>Road speed:</b> Displays road speed. Note that some vehicles (including TVR) use a different road speed transducer setup, and the measurement on those vehicles may not be updated above a certain speed.</li>
    <li><b>RPM (tachometer):</b> Displays engine speed in revolutions per minute. The redline represents the RPM limit stored in the ECU.</li>
    <li><b>Fuel temperature:</b> Displays the fuel temperature, which is also sometimes considered as the under-bonnet temperature.</li>
    <li><b>MAF reading:</b> Displays the reading from the mass airflow sensor as a percentage of its maximum range. This display has two modes:
        <ul>
        <li><i>Linear:</i> Shows a percentage of the maximum airflow. It will vary linearly as the sensor measures more mass.</li>
        <li><i>Direct:</i> Shows a percentage of the maximum sensor voltage (5VDC). It will vary logarithmically as the sensor measures more mass.</li>
        </ul>
    </li>
    <li><b>Throttle position:</b> Displays the throttle position as a percentage of wide-open throttle (WOT). This display has two modes:
    <ul>
        <li><i>Absolute:</i> Calculates the percentage by dividing the raw reading by the maximum theoretical reading. Even when the throttle is closed and resting on its stop, the "Absolute" reading will still show some positive value.</li>
        <li><i>Corrected:</i> Adjusts the minimum end of the range so that a closed throttle shows as 0%.</li>
        </ul>
    </li>
    <li><b>Idle bypass position:</b> Displays the position of the idle air control stepper motor. 100% represents fully-open (greatest airflow) and 0% fully closed (restricted airflow).</li>
    <li><b>Target idle RPM:</b> The engine idle speed that the ECU would attempt to achieve under the current conditions.</li>
    <li><b>Selected gear:</b> The state of the neutral switch (for automatic gearboxes), or an indicator that a manual gearbox is fitted.</li>
    <li><b>Main voltage:</b> The voltage at the main relay.</li>
    <li><b>Lambda trim:</b> Fuel trim that is being applied as a result of feedback from the exhaust lambda sensors. There are two types of trim applied by the ECU, referred to as "short term" and "long term". These lambda trim values are only relevant when the system is running in closed-loop mode, so this display changes to a <b>MAF CO trim</b> display when fuel map 1, 2, or 3 is selected. Note that the MAF CO trim is only updated if the engine has run.</li>
    <li><b>Current fuel map:</b> ID of the currently selected fuel map, from 1 to 5. For most North American specification (NAS) Land Rovers, this will always be Map 5. In other markets, the map may be selected with the use of a "tune resistor" in the 14CUX wiring harness. A special sixth map, Map 0, is used for fail-safe/limp-home conditions.</li>
    <li><b>Multiplier:</b> This is a value associated with the current fuel map, and it seems to be used to adjust the fueling values for the engine displacement. It will change significantly between fuel maps intended for different engine displacements.</li>
    <li><b>Fuel map:</b> Displays the currently selected fuel map as a 16x8 matrix. Each cell is colored as a quick visual indicator of the fueling values; higher color saturation corresponds to more fuel. Columns in the matrix correspond to different engine speeds, and rows correspond to different engine loads. The cell with the value closest to the fueling value currently in use will be highlighted by the software. The numbers in the header row reflect the engine RPM threshold for each column.</li>
    <li><b>Fuel pump relay:</b> The green lamp will be lit when the ECU is attempting to run the fuel pump.</li>
    <li><b>Injector duty cycle:</b> The percentage of the time available between spark interrupts that represents the amount of time the fuel injector will be open. Once this reaches 100%, the injectors cannot flow any more fuel and any additional load on the engine may result in a lean condition. Computing this value requires that the engine speed (RPM) is also being read. Note that the injector duty cycle is read from a single memory location that is used for both the odd and even banks, so it may display unpredictable behavior during closed-loop operation (when the banks are being fueled based on different lambda feedback.)</li>
    <li><b>Pulse width:</b> Fuel injector pulse width in milliseconds. Like the injector duty cycle, this is read from a single memory location that is used for both the odd and even banks. Note that it may be possible for this value to exceed the available time between spark interrupts, which would mean that the engine is being under-fueled.</li>
    </ul>

    <h3>Options dialog</h3>
    <ul>
    <li><b>Serial device name:</b> The name of the serial device connected to the 14CUX. If running Windows, this will be something like "COM2". If running Linux, it will be something like "/dev/ttyUSB0".</li>
    <li><b>Speed units:</b> Sets the preferred units of velocity for the road speed display.</li>
    <li><b>Temperature units:</b> Sets the preferred units of temperature for the coolant- and fuel-temperature displays.</li>
    <li><b>Enabled readings:</b> These checkboxes allow the user to enable reading only certain parameters. This allows the limited bandwidth of the diagnostic port to be used for only those parameters that interest the user. If fewer readings are enabled, they will update more quickly and smoothly than if all the readings are enabled.</li>
    <li><b>Periodically refresh fuel map data:</b> When set, this causes the fuel map contents to be re-read from the ECU every few seconds. This can be useful when running a ROM emulator to tune a map on a running engine.</li>
    <li><b>"Soft" fuel map cell highlight:</b> Causes the display to show the weighted average of the four active fuel map cells by shading them in the same proportion. If this option is turned off, the display will round to the nearest row/column and show only a single cell as being active.</li>
    </ul>

    <h3>Idle air control dialog</h3>
    <p>This dialog allows the user to drive the idle air control (IAC) valve in the intake plenum. <b>Because the ECU is adjusting the valve when the engine is idling, it is recommended to only test movement of the valve when the engine is off.</b> Otherwise, unpredictable behavior may result.</p> 
    <p>The motor controlling the valve has a total of 180 steps of movement, so commanding it to open or close by 180 (or more) steps will ensure that it reaches its fully-open or fully-closed position (assuming the valve is functioning mechanically.) Note: after the IAC valve has been moved from its fully-open position, the ECU will only allow it to return to a maximum of 99% open until the next startup. This is normal behavior.</p>

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